Effect of Equivalent Sites on the Dynamics of Bimetallic Nanoparticles

Abstract

Using a Sutton and Chen interatomic potential, we study the molecular dynamics of AuPd nanoparticles with an initial icosahedral structure at different temperatures and concentrations, where each relative concentration of the 561-atom particles was made by placing atoms of the same species at equivalent sites, in order to identify under which conditions the melting transition temperature appears for each particle. In addition, we compute global order parameters in order to correlate the obtained results with the caloric curves of each particle. As a result, we observe that the melting transition temperature depends on the relative atomic positions of gold and palladium. The melting transition temperature of the Au-Pd alloy particles appears at higher temperature than that of the pure-gold particle. From the analysis of the structure of the particles, we found that the melting temperature increases with the proportion of gold atoms, and for those particles with a higher concentration of palladium on the surface, we observe an early migration of gold atoms before the melting transition temperature appears.

Stability of Au–Pd Core–Shell Nanoparticles

“…Several nanoalloys have been studied either within a theoretical approach , or experimentally. , From the theoretical perspective, for example, the structural rearrangement of Au–Pd small clusters on a titania substrate has been investigated using MD under spin-polarized Kohn–Sham density functional theory (DFT) . The authors found that at finite temperature the Pd atoms migrated to the outer surface of the cluster, producing potential active sites.…”